Telephone system



Aug. 15, 1933.

D. A. CHRISTIAN TELEPHONE SYSTEI Filed April 13, 1931 a Sheets-Sheet 1 JL 1 A v JR BWEL JPSL emu? JPS Fig.1.

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5 Inu'en at Aug. 15, 1933. D. A. CHRISTIAN 1,922,232

TELEPHONE SYSVTEI Filed April 15, 1931 s Sheets-Sheet 2 Fig. 2.

Aug. 15,1933. 7 HR|$T|AN 1,922,232

TELEPHONE SYSTEMv Filed April 13, 1931 3 Sheets-Sheet 3 Inua'n'lnr' David Edam 511+ zan Eli-1g.

l 1 ber of subexchanges which in turn may be linked U50, anextra digit have to becatered to.

Patented Aug. 15, 1933 TEIS TELEPHONE SYSTEM David Adam I Christian,

London, England, as-

signer to Siemens Brothers 8pCompany Limitcd, London, England Application April 13,1931, Serial No. 529,680,

and in Great Britain April 25, 1930 30 Claims. (01. 179-18) The present invention relates to *telephone systerns and is more particularly concernedwith setting up connections between different exchanges'over junctions.

5 In urban areas it is common to have a main 7 central exchange linked by junctions to a mum by junctio'ns to Satellite exchanges, the junction layout being determined by the traffic require- 1 merits of thearea. Inrural' areas a different problem is often encountered in that a number of exchanges are frequently found lying more or lessalongla line as in the case of small towns or villages along the banks of a river.y It is then Iuneconomical to provide junctions between each exchangeand everyother exchange in the area or between a central point and every other exchange,and as the junctions between two adjacent exchanges follow thesame route as, junc- 26 tions to more distant exchanges in the saine direction, an obvious method of linking up the several exchanges of suchan area is to connect eachexchange with the adjacent exchanges on either side of it by means of junctions and to extend connections tomore distant exchanges over a number-of serially connected junctions. Ifhe problem that then presents itself where automatic switching arrangemehtsare concerned is the most satisfactory wayof setting, up a con- 30 nection between any two exchanges in the area.

Severalmethods are-available butsomehave se-.

rious drawbacks to theiradoption. Tornention one such' nethod, a first digit dialled may determine in which direction the connection is'to be extended and further digits would" then take offectiri setting switches in the serially-connected exchanges until the required subscribers line is reached. It will be seen at once that sucha method involves different digits being dialled at diilferent exchanges to call a particular exchange" and if there'are a number of exchanges in the area, a large number of digits would in some cases be requiredtost up a connection. Digit translating arrangements couldof, course be provided, in order that a subscriber may be called by dialling the same digits irrespectiveof the exchange at which the call originates'but this would prove costly, particularlywhere specialcfacilities such as rural party lines requiring According to one feature of this invention each exchange of the system is-connected, with the adjacent exchanges on each sid'eof it byjunc tions and provision is made for associating free junctions between adjacent exchanges to the free route between the exchang route. 'Whenajunctionis taken into use no exchange. In the case=oi-the desired exchange end that as far as may be possiblehaving regard to junctionoccupation there is always a waiting es at each end of a chain, of exchanges.

The junctions may be associated 'so that there ;is a chain of free junctions inreadiness for a connection but no actual connection between one junction and the next adjacent junction exists until a junction call is'niade. As many serially connected junctions may then be taken into use 7 as arerequisite to extend the route to a desired exchange, and the otherwaiting junctions, are

free to be used in the preparation of another through route.

For the preparation of a route'junctions incoming. at an exchange may terminate in searching switches which are maintained in connection with free outgoing junctions for the extension of a route so far 'as there are free outgoing junctions. No seizure of; a junction however need be made andinone arrangement according to the invention itis, arranged that an effective connection of adjacent junctions is made depending on an operation at the exchange at which a call originat'esfi l According to a further feature of theinven tion it is arrangedthat successive "junctions are taken into use consequent on the receipt at an exchange attire-incoming end of a junction of i a single currentirnpulsf For the'connection of serially relatedjunctions'a train oi impulses nlay be transmitted from theiexchangeat Which the call originates, eachimpulse ofthe train eifecting the connection of a further junction to the circuit 'isclosed theteover until an impulse .of a

"routesetting digitis transmittedand it may be arranged that themake period of an impulse energizes a line" relay at the incoming end of the junction, the de energization oifthe the relay, consequent on the transmission of the break of thenext impulse eilecting-theswitching throu'ghof the junction to the next adjacent-,-

the operation of the line relay at this exchange takes place consequent upon theprolonge-d closure of-the circuitover the junction on the cessation of impulse transmissionl thereon, and time is given for afslow operating relayto operate and prevent conri'ectionof a furtherjunction section. Thisrelay may close a'circuitfor the searching switch at the incoming end for the junction Wherebyit is caused to advance in search of efreeoutiet to local switches. Theslow operating relay atihtermediate exchanges wouldbe ing device or the like.

rendered unoperative when an extension of the junction route is made.

In order to obviate, for the calling of a particular exchange, the dialling by a subscr'ber of trains comprising diilerent numbers of "impulses according to the positionof the calling and called. exchanges in the chain it is arranged that a certain maximum number of impulses is always dialled for the route setting train and certain of these impulses are suppressed at the originating lecting switch which in accordance with the value of the digit searches for a freeoutlet in the direc tion of the required exchange, i. e. to the left or right or over local switches, and marks a count The second digit is predetermined and comprises at least the maximum number of impulses that will be required for the interconnection of the extreme exchanges, this may be for example the digit 9. The impulses of this digit cause thecounting device to operate and count the impulses and at the same time the impulses are transmitted'over the selected outlet. When the counting device reaches the position marked by the first dialled digit further impulse repetition over the selected-outlet is suppressed. In the case of a local call all the impulsesjof the route setting train may be suppressed.

In the preferred form the counting device consists of a simple steppingswitch which may be embodied in the first selectorat an exchange. Contacts in a bank of the switch are or ss connected to a set of contacts corresponding to groups of selector outlets, the group in which an outlet is selected being marked, and atest relay connected to the wiper oi the counting switch coactingwith the cross connected contacts is arranged to operate when a marked contact is reached and short circuitthe-impulse receiving contact in the outgoing wires. This short circuit is removed at the end of the digit by suitable means to enable further impulse trains to be transmitted without translation for the setting of switches in the desired exchange.

In a system in which a simple connecting circuit is employedand connections are completed over a connector operatedunder the control of or in conjunction with a controlling device, the connector may be stepped automatically when the controllin device is taken into use to a *r o 7 0 cup of contacts overwhichit may search for a free junction in one direction in response to the first digit received. If however the first digit received direction .over which it searches automatically.

In the case of a'local call the connector would be released from the position to which it was stepped automatically and the succeeding digit would be absorbed. a

In a system of this kind when a controlling device is taken into use at each exchange ining unnecessary.

volved in a connection it may be arranged that a junction is only marked available for use when a controlling device is associated with the searching switch (preselector) at its incoming end. Alternatively to this arrangement search for a free controlling device may take place when the demand arises and a second dialling signal is given after the second digit has been dialled.

- The above described arrangements contemplate theuse of one-way junctions but we may provide for both-way junction working by arranging changeover contacts of a relay at each end of a section so that the junction is always connected to incoming preselectors at each end.

When such a junction is taken into use the relay controlling the change over contacts at the outgoing end of a desired junction is operated to change over the contacts to extend the connection to the next junction section. Incoming preselectors at the originating exchange, as regards the direction of the call considered, which may be resting in contact with the junction taken into use, would then step in search of another free junction and preselectors at the end of a junction incoming from the opposite direction at the distant exchange, would act in a similar manner.

If an incoming preselector is unable to find a free junction section, it may come to rest on contacts associated with a busy signal circuit so that when it is taken into use the calling subscriber will receive a busy signal.

The arrangements of the invention lend themselves to the adoption of multi-metering, i. e.

metering of calls according to the exchange to which the call is made. .A convenient method of determining the fee to be charged for a call is to prepare the metering circuit over contacts operated as determined by the first digit dialled.

The arrangements, lend themselves to mixed automatic and manual exchanges in an area. In the case of a terminal manual exchange, the operator thereat may dial the required number of impulses to extend the junction sections to the wanted exchange, inst of the exchange determining digit, a controlling device then be- At an intermediate manual exchange, the incoming preselectors terminating junction sections, which preselectors would still be provided, may have access to the answering equipment for the purpose of dealing with local calls. The multiple jacks would take the place of levels in the selecting switches in an auto matic exchange and would be multipled to the junction outlets from the incoming preselectors.

Reference will now be had to the accompanying drawings which show by way of example a method of carrying out the invention. Fig. 1. shows in diagrammat cform the arrangement of switches and connections at an exchange having junctions outgoing to the left the right of the figure, the junctions being used for traffic in both directions. Fig. 2 shows a first selector at an exchange, the selector having combined with it a counting switch which is marked by the exchange determining digit controls the transmission of impulses for the connecting up of junction sections until the desired exchange is reached. Fig. 3 shows a preselector connected to the incoming end of a junction which preselects junction to the next exchange when the junction to which it is connected is taken into use it extends the connection either to the next junction section or to local switches. Fig. 4 shows an equipment for connection between the and the right.' The junction JL incoming from it end iof"af jiinction and the junction preselector when the junctionisto' be used for trafiic inboth "directions. ,t l q i i Referringnow to FighL-the switches indicated diagrammatically at the foot of the drawings fromleft to? right are subscribefls preselector PS 'connecteci' to the line from a subscriberSUB,

second preselector PSS, first selectorlS, intermediate selector GS, and fine-l selector In the upper tart 'of thedrflwngsi indicated junctions outgoing to orincomingfronq the left the left ofthe figure is connected over ecu inenlt BWEL when it is to be used for both ay working to the junction preselector JPSL,

of the banks of which aremultipled and connect ed to the eqiiipment BWER; and tofccntacts in levels of the first selectors siich as IS. Another part of the banks of the preselector JPSL is connected to ncoming selectors such as iiCS,.t-Tne bank contacts of which multipied. to thoseci intermediateiselectors such as and connected 'to fi n al selectors such as F5, The junction JR onf" the right of the figure is connected overthe e'quipment BWER to; the junction preselector JP$R,-thebank contactsof which are connected me similar mannerto those of JPSL. If one way junctioirworking only is to heeinployeti, junction JL if incoming from they left would be connectedidirectly to JPSL, the bank contacts of which. concerned with junction connections would'be connected. directly to junctions such as JR outgoingto thejright oijthe figure; the junc- If" wl'ientaken into use. Incoming junctions from the right such as JR and preseiector would then be connected in a similarmanner, th mul tipleci connections betwe n the incoming preselccto rsjand the first selectors rciiresented by 7 IS and the connections to incoming selectors rop resented by ICS being made as before.

The system as show: inthis f1 ure isarranged fii'stcligit denoting th reqniredexchangestepten into use over PS and l PS8 to a level i giving acce ping a first selector ss to junctions leading Lthe direction of the required exchange or to goutlets to local switches ccorcii-ng to thegdigit dialled; Theseconiihei isaiways 0 a ni mberoi impulsesof this digit are cotinteci cfi d rinineii by the first digit dialled. to effect completion of the jtlIlCtjlQlfiCOi'llflGCiliQil to the reqnir ecieirchange ifl the callie oneto be won ple tecitioi er junction. The Brrl /ith and 5th digits effect the settingoi theintermediate crincoininaselector the case maybe and'the final selector. Selectors ICS, G-SantlFS are of aizi cl l lSi ii iuy, employed for the purposes-they serve haying regarcl to the system of impnlsing itesting and s'up'eryision at the exchange where they are situated land' 'the tre-selectors ES and PSSrnay beswitchesof any suitable imotfxzn type.

i i i i Fig. asno s a f rst selector of thetwo n c otion:

type in which impulses are receivecl on an im pulse relay A connectedin the incoming side of a feeding bridge and are-repeated ovencontactal to the yerticalmagnet V'Mof the selectoranci aft er seizure of a free outlet in theievel to which the selector is set'by impulses, the irnpuises are re s peatetiover contact 2 and the utgoingb wire. The test fora free selector andfree outletis batterypotential onthe testwire.

Yilis the answeringsupervisory relay operated when the calledsubscriber replies by' the apply ret bridge. and T the test re Jy. The rotary and release direct tirive type iector, the contacts vs correspondi the switch the vertical 0 operated} contact [c1 opei he the operating cir canon 'of battery to the ct wire either overthe arcl coil RC and the subscriiaers looporfrom a connection made at subsequent feeding V is the reieaserelay, D a dialling relay magnets are clesig; atecl RM andZM respectively. Vertical ofi-norinai contacts are denote by I: Withanumer alsuffix. Associate-:1 with the'first selector is a s Action counting switch of the lei/h1g2 winers designeted AS, Wiper co-acts Wit an arc of contacts which are cross-connected e" "equired; to a, set of contacts cs which are briclg ocito a co takes only inthe vertical mot over Wlflfii :lg' (ilD'ofrelay A, con tacts tothe incoming testwire c. jRe iay one "es in this circuit to earth. connected at the subscribers preseiector end at ccntactai section is sw' chetl through at the dings (I) and (II) of relay A i. On the operation ofrelay f a circuit is cio at contact oil for relay'Dan i a circuit is closed over a resistance to incoming 0 w re tor-guard against the subsequent the first in tests feeliy reason of a battery the siow releasing release relay V'.

g of contacts and k2; Contact 03 opens tesponding of ear-tired contacts by a wipcrVS which 90 a pal t in the circuit of. the release magnet ,Zli i, and loses anoint in the circr. or the rotary magnet RM; contact 424 cpensa point in the f homing circuit for the single motion switch Reiay D operating prenares a holding CilCliitfOi itself at contact (i1 opens a point in the test circuit at contact cit-energizing" incline (III) of relayA. Contact (13 prepares the VH3:- tical m gnet circuit. A further Contact of ref la? is") I y connect ache-Hing" signal transformer to the line if a sired. i V

f the wanted. number and relay A the impulses of tiie digit. i I

These impuises are repeated; at cont; t al in a lcircuit including winding VM of thet vertic ai magnet, contacted-3 anti and the switchflis responds to stepped i ertically i'n accordance with the number of impulses received. At thefirst step talten by cuit of relay D ch thereafter depends fcixits cnit over the baclcoi Contact operation on a anti. the front of contacts 21, k1 and c1, Consubscriber new the first digit ormal contacts are tact k2 opens in the test-in circuit against the reiease oi relay D, contact c3 closes a further point irrthe circuit of the rotery magnet. When 1 relayh re-operates the endof the first impulse,

contactaii closes inits front position la circuit 'iorlrelay L which thereupon operates and locks up over contacts Z1, lei anclol and contact Z2 prepares the circuit of the test relayT oyer its winding. (1) and contact 13 prepares the circuit no function this stage. Atthe end of the inn-- pulse train relelyA remains steaciiy operated and ,relayD releases closing a circuit formagnet RM magnetltltfl Other contacts of relay .Ahave,

at contact d3. The rotary magnet is operated from battery connected to it over an interrupter and the selector wipers are rotated over the level in search of a free outlet. When such an outlet is found relay T operates by means of its winding (I) and locks up over its winding (II) and contacts t1, (11, A21 and v1. The rotary'magnet circuit is opened at contact t7 and contact t4 connects earth directly to the test wiper to mark the outlet engaged. Contacts t2 and t3 close in the a and b wires and contact t5 prepares a circuit for magnet DM of the single motion switch. Contact t6 closes a circuit over contact 03, for relay C which thereupon operates and prepares a holding circuit for itself at contact 01.

Referring for a moment to the connections between the contacts es and the bank of wiper AS, the contacts corresponding to levels of the selec-' tor are connected to contacts in the bank of wiper AS, the contact corresponding to the level from which outlets to a local group selector such as GS (-Fig. l) are taken being connected to the normal contact of the switch on which wiper AS rests when the switch is not in use. The vertical wiper VS connects earth to the contact in the bank of wiper AS corresponding to the level to which the switch has been stepped and in the case of calls to be completed locally earth is also connected over the normal contact to wiper AS.

As regards the outlets from the selector itself, outlets to a group selector for the completionv of local calls are connected in one level and outlets to junctions going out in one direction such as junctions J L (Fig. l) are connected in levels corresponding to the digits denoting exchanges in that direction, contacts in the several levels concerned being commoned if necessary. Outlets to junctions going out in the other direction such as junction J R are connected in levels corresponding to digits designating exchanges in that direction.

Continuing with the description of the operations of the first selector it will first be assumed that the call is one to be completed locally. In this case earth will be connected by wiper VS to the normal contact in the bank of wiper AS as well as to contact 5 it being assumed that the initial digit of subscribers in the exchange under consideration is 5, consequently on the operation of relay T, contact a4 being open relay S operates and at contact sl opens a point in a short circuit connected over the front of contact a4 about its winding. Relay C being operated a short circuit is closed over contacts 32 and 02 about contact a2 preventing repetition of the second digit. over the switch. On the commencement of the first impulse of the second train a short circuit is removed from relay E at contact a6 and this relay operates and prevents the short circuit being re-imposed on the termination of theimpulse by opening contact c1; contact 62 closes in the outgoing 1) wire and contact e3 opens in the operating circuit of relay C leaving this relay dependent on the back of contact a6 for its continued operation. This train of impulses is without any effect on the circuits shown in this figure if the call is a local one and at the end of the train relay C releases. The short circuit is now removed from contact a2 and the impulses of subsequent trains are repeated by it to complete the setting up of the connection. When the called subscriber replies to the call relay Y operates and at contact 112 releases relay L. Relay L is however slow in releasing and during its release period current in the eeaesz 0 wire is increased due to the parallel connection of battery over winding (III) of relay A, contacts yl and Z4 and the subscribers meter is operated.

At the end of the conversation and when the calling subscriber replaces his receiver on its hook relay A releases and at contact alopens the circuit of relay V. After a brief interval relay V releases releasing relay T at contact 01 and contact t4 initiates the release of subsequent switches and relay Y releases. Contact t6 releases relay E, and contact t8 releases relay S and contact t7 closes the circuit of the release magnet ZM. The

selector wipers are now restored to their normal position and the restoring of the vertical off-normal contacts opens the circuit of magnet ZM at contact 763.

If a call is to be made over a junction the first digit dialled will be that corresponding to the exchange to which the wanted subscriber is connected. The selector will be stepped to a level depending on this digit, the level containing outlets to junctions leading in the direction of the wanted exchange. Accordingly after the end of the first train of impulses earth will be connected by wiper VS to the corresponding contact in the bank of wiper AS (not contact 5) but relay S will not operate at this time as wiper AS is resting on its normal or home contact. When a free outlet has been found relay T operates and closes a circuit in which relay C operates as before but as relay S is uno erated relay A repeats impulses of the second train over the junction seized at contact a2, The second digit is 0 and on the first impulse break taking place relay E operates and leaves relay C dependent for its continued energization on the back of contact a5. Contact e2 closes and at the end of the impulse a circuit is closed over the 2) wire at contact a2 to cause the preselector connected to the incoming end of the junction at the next exchange to prepare to switch the junction through. This operation will be more fully described later with reference to Fig. 3. Relay S being unoperated, each time relay A releases a circuit is closed from battery over contacts s3, t5, a5 magnet DM to earth. The counting swich is in consequence stepped until wiper AS is stepped onto the contact earthed over wiper VS whereupon when relay A reoperates a short circuit is removed from relay S and the relay operates opening the magnet circuit at contact s3 and short-circuiting contact a2 at contact $2. The remaining impulses of the tenare not transmitted over the junction but are repeated at contact at for the maintenance of relay C. After the last impulse of the ten has been received by relay A relay C releases and opens the short circuit about contact which is now closed and impulses of further trains are repeated at contact a2 for the setting of switches at the distant exchange for the completion of the connection. 1 I

When the connection is released by the calling subscriber the counting switchis rotated to norinal by the energization of its magnet DM in a homing circuit over wiper BS and the off-normal segment, contact 124 and an. interrupter.

It will be noted that the counting switch permits a'deflnite number of impulses to be transmitted over the junction as the second digit, the number being determined by the first digit dialled. As the second digit is always 0 any number of impulses from l'to 10 can be transmitted and each impulse effects the connection of a further junction section until a route to the wanted exchange is built up.

erate the'answering supervisory relays at preceding exchanges.

When the calling subscriber clears relay PL releases releasing relays PR, PQ and PT and PY and the release of succeeding switches is, ini-' tiated. If the test connection is a local one the release of relays PQ and PT connects magnet PDlVi over wiper JC to the 'earthed contacts and those on the right (lower) to JPSl-t.

the switch is stepped until the first contacts connected to an outlet to a free junction is met and the. switch comes to rest with its wipers on such contacts.

If the junctions are worked in both directions then a special equipment such as that denoted by BWEL or BWER (Fig. l) is connected between the incoming end of a junction and the junction preselector. The equipments BWEL and BWER are identical and one of them is shown in Fig. 4; for convenience this will be assumed to be the equipment designated BWER in Fig. l and the junction wires on th right of Fig. 4 (upper part) will be assumed to be the junction JR. The wires on the left will be connected to JPSL and IS and In the case of a call incoming over the junction JR the operation of the test relay in the preceding circuit connects earth over relay'Y or PY as the case may be to the junction a Wire and this connection extends over contacts corl and $12 and relay ETR to bat- 1 tery. Relay ETR iscf high resistance and operates but the answering supervisory relay in series with it does not. Contact ctrl' disconnects relay COR. and connects earth to the junction multipled in the banks ofJPSL and IS (Fig. 1) to mark the junction engaged and to cause JPSL to step on and preselect another free junction. The con- 'nection of battery to the incoming junction 1) Wire operates relay PL in JPSR as previously described. When the junction is worked as a both wayjunction a third incoming wire is connected to the incoming preselector this wire being connected to battery over relay SR in the equipment BWER and on the operation of relay PR earth is connected to this wire at contact prl to operate relay SR.

Relay SR operating contact s'rl opens a further point in the circuit of relay COR and prepares an alternative earth connection to :the junction in the multiple which circuit is com- I, pleted on the release of relay E'IR at contact 312. -The setting up of the connection now proceeds as before described.

If a call is incoming from junction Jhover the equipment BWEL and preselector JPSL or over a first selector in the exchange in which the equipment under consideration is situated earth will be connected to the wire on the left of the Fig. 42 by the operation of the test relay in the preceding switch and relay COR operates. The earth h connection to wire (2 marks the junction engaged and contacts corl and, 0012 switch the connection through over junction J R to the next exchange.

On the release of a connection relay SR or COR as the case may be-are released and the equipment is restored to its normal condition. What I claim as new and desire to secure by Letters Patent is:

1. In a telephone system, a plurality of exchanges, junctions connecting the exchanges in tandem or serial relationship, and means in each intermediate exchange for associating free juncs changes, junctions connectingthe exchanges in tandem or serial relationship, and pre-selecting switching devices in each intermediate exchange for automatically associating each free junction with a 'free junction leading to an adjacent exchange.

3. In a telephone system, a plurality of exchanges connected by junctions in tandem or serial relationship, means in each intermediate exchange automatically operated for associating free junctions from one of the adjacent exchanges with free junctions from the other of the adjacent exchanges to maintain a free route through the series of exchanges, and subscribercontrolled means for effectively interconnecting associated junctions.

. 4.'ln a telephone system, a plurality of exchanges connected by junctions in tandem or serial relationship, means in each tandem exchange for automatically associating free junctions from one of the adjacent exchanges with free junctions from the other of the adjacent exchanges to maintain a free route through the chain of exchanges, subscriber controlled means for seizing ajunction and for transmitting a series of impulses thereto, and means controlled by the impulses for effectively interconnecting associated junctions. I

5. ma telephone system, a plurality of serially related free junctions, means for taking the first junction of the series into use and for transmitting a series of impulses thereto, and means responsive to said series of impulses for progressively interconnecting adjacent junctions.

6. In a telephone system, a plurality of free junctions, automatic switches for associating said junctions in tandem or serial relationship, means for transmitting a series of impulses to the first junction in the chain, and means responsive to said impulse series for progressively connecting the junctions, said means comprising means in each switch operated responsive to a single one of the impulses of the series.

-7.' In a telephone system, a plurality of exchanges connected by junctions in tandem or serial relationship, means in each tandem exchange for associating together free junctions extending to the respective adjacent exchanges, means controlled by a calling party in an intermediate exchange for selecting a free junction extending to one of the adjacent exchanges, and means controlled by the calling party for effectively connecting the selected junction with the associated junction in said adjacent exchange.

8. In a telephone system, a plurality of automatic exchanges connected by junctions in tandem or serial relationship, means in each exchange for associating free junctions extending to adjacent exchanges, subscribers lines terminating in the exchanges, subscriber-controlled means for transmitting series of impulses over the line, means responsive to the first series of impulses transmitted over a line for selecting a free junction extending from the exchange terminating the line, and means responsive to the second series of impulses transmitted over the line for progressively connecting a plurality of associated junctionsto extend a connection from the line to a wanted exchange. v

'9. In a telephone system, a plurality of automatic exchanges connected by junctions in tandem or serial relationship, means in each exchange for automatically associating free junc-,

tions extending to adjacent exchanges, a sub scribers line terminating in one exchange, means serial relationship, a hunting switch for;

the junctions, and means responsive to junction;

fortransniitting series of impulses over the line,

means, responsive to the first seriesof impulses transmitted overthe line for {selecting a free junction to an adjacent exchange and f designating a particular oneflof the plura y of exchanges as a wanted exchange, and means-re sponsive to the second seres of impulses nd dependent onthe value of the' firs t series ,nection from the line to the designated exchange.

,lOLIn a telephonesystein, a plhrality oif' changes ,connectedby junctions in, tandem or junction, said switches being arranged to select a free junction exte ing to an ad exchange, means for, transmitting i. .ipu.

ceiptof an impulse over ajunction for ng the associated switch to seize preselected 11. In a are connected by junctions in tandem or serial relationship, means for seizing a junction in any exchange, means for trahsniittinga series of impulses ,over the seized junction, and means re s'ponsive to said impulses for progressively con .necting other junctions to the seized junction one junction being connected for each impulse of the. series,

changes connected by junctions in a chain, means necting the seized junction to a junction extending to an adjacent exchange, and means re sponsive to each succeeding impulse of the for connecting the junction last'connected with q to a junction extending to 1 farther along in the chain.

an exchange located.

13; In a telephone system, a switch, means for,

transmitting series of impulses to the switch,

means in the switch operated responsive to the first series of impulses for setting the switch, means inthe switch for repeating a portion of the second series of received impulses, the re peated portion depending on the initial settingof the switch. i h

14; In a telephone system, a selector repeater switch, means for transmitting series of impulses to the switch, means responsive ,toithe first series of impulses for setting the switch in selec tive relation to a group of junctions, means in :the switch for automatically selecting an idle one of said junctions, and means in tlie switch for repeating a portion of the second series of impulses over the selected junction, the number of impulses repeated depending on the initial setting of the switch.

15. In a telephone systema'selector repeater switch, means for transmittingseries of impulses to the switch, means responsive "to the first series A of impulses for setting the switch and for deter- 1 mining the portion of the second series of 1mrepeating of all impulses of subsequent series transmitted to the switch, i

M 16. In a telephonesystem, a selecting switch and an associatedauxiliaryiswitch, means in the first switch for responding to a plurality of series of impulses, means responsive to the first n pulses ,for progressivelyconnecting associated an idle one of said junctions means responsive telephone system in which exchanges h h h case the contact marked by the first 12; In a telephone system, a plurality of ex" switch. for seizing a junction and for transmitting a series of current impulses thereover, means re sponsive to the first impulse of the series for con series Goiimpulses for setting the'first switch in selective relation to a group of junctions and for marking a contact accessible to the second switch means in the-first switch for automatically SQ? looting and seizing an idle junctioninthe'selected group, and means responsive to the second; series ofimpulses for operatingsaid second switch and for simultaneously repeating the impulses over the seized junction until the second switch con nects withsaid marked contact.

17. Ina telephone system, a selecting switch and an associated auxiliary switch, means for es cl impulses to the first switch, means responsive to the first series ofimpulses forl setting the first switch inselective relation to a group of junctions and for marking a contact accessible to the second switch, means in the switch for automatically connecting with to the second series of impulses for operating the secondswitch one step for each-impulse of the series and for simultaneously repeating the impulses, over said one junction, a relay oper ated responsive to the second switch connecting with said marked contact, and means controlled lay saidrelayfcr disabling the last said means.

18. A telephone system as claimed in claim 17 in which the au' iliaryswitch is not operated and no impulsrn oi second repeated in,

switch is 95 the contact normally engaged by the second 19. In combination, a junction terminating in a hunting switch, two groups of junctions accessihle tosaid switch, means for closing a air- 0 cuit over the first junction, and means controlled by the duration of said circuit closure for de termining the group in which the switch will seize a junction. 20 A switch having access to two groups of 115 outlets, a line relay for the switch, means for transmitting impulses or" different length to the switchto operate saidrelay, and -means controlled by the duration of theoperation of said relay for determining the group of outlets over which a connection will be extended; 1 V j 21. A switch having access to two groups of outlets, two test wipers for testingfthe outlet groups, respectively, means for transmitting impulses of different lengths tothe switch, and L means dependent on the length of the impulse for rendering one or the other of said wipers effective. i h 21A switch having access to two groups of outlets, means for operating the switch to select an outlet in one group, means for transmitting a long or ashort impulseto the switch, means responsive to a short impulse for operating the switch to seize the selected outlet, and means responsive to ,a long impulse for operating the 1355' switch to select and seize an outlet in the other group; i I i 23. A switch having accessto two groups of outlets, means for transmitting a single impulse or a series of impulses to the switch, means in 144-0 the switch responsive to the receipt of a single impulse for operating the switch to connect with an idle outlet in one group,l,and means in the switch responsive tothe receipt of the first impulse of aseries for operating the switch to seize an outlet in the other group and for rendering the switch effective to repeat subsequent impulses of the series over the seized outlet.

24:. In a hunting switch, a line relayand a test relay, means for energizing the line relay for either a short interval or a long interval, means controlled by the line relay for preparing a circuit for the test relay upon energizing and for completing said circuit upon releasing provided the line relay has been energized for a short-interval, and'means including a relay energized provided the line relay has been energized for a long interval for preventing the completion of said circuit.

25. In a telephone system comprising a plurality of exchanges, two-way junctions connecting the exchanges in tandem or serial relationship, hunting switches associated with both ends of 'the junctions, means for maintaining said switches in selective relation with idle junctions extending to adjacent exchanges, means for seizing a junction at one end, means responsive to said seizure for disconnecting the associated switch at said one end, means for transmitting a current impulse over the seized junction, and means controlled by said impulse for causing the associated switch at the other end of the junction to seize the pre-selected junction extending to the adjacent exchange.

26. In a telephone system, a plurality of unconnected serially related junctions, means for taking the first junction of the series intouse, means for transmitting a series of evenly spaced impulses over the first junction, and means responsive'directly to the impulses for progressively connecting the associated junctions.

27. In a telephone system, a plurality of serially related junctions, a switch terminating each junction and associating it with the next adjacent junction of the series, means for taking the first junction of the series into use, means for transmitting a series of impulses over the first junction, and means responsive to said impulses for progressively operating said switches to connect associated junctions while the impulses are being transmitted.

28. In an automatic switch adapted to respond to two series of impulses, means for positioning the switch responsive to the first series of impulses, and means for repeating a variable number of the impulses of the second series dependent upon the positioning resulting from the first series of impulses.

29. In a switching device, means for responding to two series of impulses, means for repeating a variable number of impulses of one series, and means controlled by the other impulse series for controlling said first means.

30. In a switching device, means for responding to a plurality of series of impulses, means for setting the device responsive to the first series of impulses, means for repeating a variable number of impulses of the second series of impulses, and

means for repeating all impulses of subsequent 

